Closing the major biogeochemical cycles

This article synthesizes case studies and research on agroecological transitions designed to close the biogeochemical cycles of carbon, nitrogen and phosphorus. It examines levers such as biological nitrogen fixation, soil organic matter storage, manure recycling, and tighter crop-livestock integration. The authors highlight the need for research in soil biology, root symbioses, waste valorization technologies and modeling, involving controlled experiments, field trials, and long-term observatories. Practical actions are discussed at scales ranging from rhizosphere interactions to landscape territories, with examples of improved nutrient access, enhanced resource efficiency and lower emissions.